Copyright law governs the rights of authors, artists, and other creators of original works of intellectual property. Copyright law gives the creator of a work the exclusive right to reproduce, distribute, publicly perform, publicly display, and create derivative works from that work.
The creator also has the right to prevent others from doing these same things.
The copyright owner is usually the person who created the work. However, in some cases, a company or organization may own the copyright.
For example, a newspaper may own the copyright to all of the articles that it publishes. If you write an article for a school website and you are not an employee of the school, then you likely have no rights to the copyright in your article.
If you want to use material from a copyrighted work without permission from the copyright owner, you may need to get permission from either the copyright holder or from the person who owns the rights to that particular piece of intellectual property. You can find information about copyright permissions on websites like Copyscape or PermissionWorks.